Process of treating feldspar for use as a fertilizer.



CHARLES WILLIAM DRUBY, OI

xrnesron, on'rnaro, CANADA.

IPROCESS OF TREATING- FELDSPAR FOR "USE AS A FERTILIZER.

No Drawing.

To all whom it may concern:

Be itknown that T, GHARLEs WILLIAM DRURY, a subject of the Kin of GreatBritain, residing in the city of ingston, 1n the county of Frontenac,Province of Ontario, Canada, have invented certain new and usefulImprovements in Processes of Treating Feldspar for Use as a Fertilizer,of which the following is a'specification.

Common or potash feldspar is a silicate of aluminum and potassium, andbeing insoluble in water or dilute acids is not available as a source ofpotash for fertilizers or other purposes without special treatment, andmy object is to devise simple and cheap means for treating the feldsparto make it available for use as a constituent of fertilizers or fortreatment for the recovery of the potash and alumina.

In the present known processes for the treatment of feldspar, the aimhas been to obtain the potash content of the spar in-the form of asulfate or chlorid, either of which is readily soluble in water and istherefore recoverable by leaching. As the reagents necessary to convertthe insoluble potash content of the spar into a soluble form areexpensive, and as the whole of the potash is not rendered soluble, theseprocesses are too expensive for commercial use on a large scale. I aim,therefore, not to obtain the potash as a chlorid or sulfate, but to soact on the spar that the resulting product though still a silicate ormixture of silicates, is readily decomposed by a dilute acid, or even bythe acids of the soil.

I attain my object by heating the feldspar with calcium oxid (lime) orcarbonate (limestone) and iron oxid (oxid ores). Some carbon in asuitable form is usually added, as ferric oxid is usually employed inthe process and the carbon facilitates its change to ferrous oxid inwhich form iron usually enters a slag.

A blast furnace will usually be employed, in which case the fuel used inthe furnace is sufficient to facilitate the reduction of the iron oxidfrom the ferric to the ferrous condition. The materials will usually bein the lump form and are suitably mixed together and with a properproportion of coke before passing to the furnace. The resultant product,when a blast furnace is employed, is a silicious slag, which, whenground, is available for use in fertilizers or Specification of LettersPatent.

Patented Aug. 117, 1915..

Application filed December 28, 1914. Serial No. 879,398.

may be further treated to obtain its potash content. The product appearsto be a mixture, or a solution in one another, of silicates of iron,calcium, potassium and aluminum, which, unlike the original doublesilicate, are readily decomposed by a acid solution. 1

Using ordinary potash feldspar (orthoclase) with the formula KAlSi O andcontaining approximately 65% silica, 18% alumina and 16% potassa, thefollowing proportions are employed in the mixture feldspar, 50 parts byweight; cal. carb., (limestone,) 30 parts by weight, or cal. oxid,(lime,) 16.8 parts by weight, and iron oxid, (oxid ores,) v15 parts byWeight. It must be understood, however, that the proportions will dependon the purity of the spar employed, the above being only a typical case,the point to be kept in mind being to use as nearly as possible just theright amount of iron oxid or calcium oxid or carbonate to obtain a fusedor sintered product.

It will be noted that the spar, lime, and iron 'oxid are practicallyinfusible separately, but when mixed in the proportion described .afused or sintered product is readily obtained. 2'

In the reaction, calcium corbonate (limestone) and calcium oxid (lime)are, of course, chemical equivalents, as when heated the carbonate givesoff carbon dioxid and the oxid remains.

It is to be understood that in the reaction, ferrous oxid'may be addedas such, or it may be the result of the reduction of ferric oxid toferrous oxid.

The reaction, as far as I can at present determine, may be expressed bythe following equations 2KAlSi 03-f-2C8CO3+F82O +C=.

This process is also applicable to the treatment of other potash bearingsilicate rocks.

It should also be understood that it is not necessary to employ a highgrade feldspar, as ordinary feldspathic rock which is more or lessimpure may be readily treated by my process.

7 What I claim as my invention is 1. A process of treating feldsparwhich consists in reacting on it with calcium oxid and ferrous oxid at atemperature of approximately 1200 C.

'2. A process of treating feldspar which consists in fusing a mixture offeldspar, calcium oxid and ferrous oxid.

3. A process of treating feldspar which consists in fusing a mixture offeldspar, calcium oxid and ferrous oxid substantially in the followingproportions by weight: 50 feldspar, 16.8 calcium oxid, 13.5 ferrousoxid.

4. A process of treating feldspar which consists in reacting on it withreagents capable of combining with silica to form a complex silicateinsoluble in water but decomposable by weak acids and the potash therebyrendered available.

5. A new composition of matter resulting from the treatment of feldsparcomprising substantially a mixture of potassium, aluminum, iron andcalcium silicates, characterized by the fact that the potassium compoundis decomposable by weak acids and the potash thereby rendered available.

6. A process of treating feldspar which consists in reacting on it withcalcium oxid and iron oxid at a temperature of approximately 1200 C., inthe presence of a reducing agent.

Signed at Kingston this 21st day of December 1914, in the presence ofthe two undersigned Witnesses.

CHAR-LES WILLIAM DRURY.

Witnesses:

' S. F. KIRKPATRICK,

J. CL GUILLIM.

